mcp-portugal defines 5 validation and lookup tools with clear, domain-specific names (validate_nif, validate_iban, validate_postal_code, list_holidays, is_holiday). All tools have descriptions (avg 120 chars, within 10 - 1024 range) and input schemas with Zod validation. However, output schemas are not documented, responses are JSON-stringified text blobs with no declared structure. Parameter descriptions are present but minimal (avg 45 chars). No error handling guidance, no pagination for list_holidays, and no tool annotations (readOnlyHint). Tools are read-only and well-scoped, but lack the polish expected of production-grade tools.

• Document output schemas for all tools. E.g., validate_nif should declare: {nif: string, valid: boolean, entityType: string | null}. This enables LLMs to extract and chain results.
• Add readOnlyHint: true to all tool definitions. Agents need explicit signals that these tools are safe to call without side effects.
• Replace example values in parameter descriptions with format constraints. Instead of 'ex.: "123456789" ou "PT123456789"', use 'Format: 9 digits or PT + 9 digits. Spaces and dots are stripped.'
• Enhance error responses with actionable guidance. E.g., if NIF validation fails, return {valid: false, reason: 'Invalid check digit', suggestion: 'Verify the last digit matches the algorithm'}.
• Add a limit parameter to list_holidays (default 1, max 100 years) and return {year, holidays: [...], total_holidays: N} to support pagination and large queries.